GENERATION. SECT. XXXtX. r. 



abforbed, or applied to thefe extended veffels, and 

 they become permanently elongated, as the fluid in. 

 cPnta& with them foon lofes the oxygenous part, 

 which it at firft pofTeffed, which was owing to the 

 introduction of air along with the embryon. Thefe 

 new blood-veifels approach the fides of the uterus, 

 and penetrate with their fine terminations into the 

 veflelsof the mother; or adhere to them, acquiring 

 oxygene through their coats from the paffmg cur- 

 rents of the arterial blood of the mother. See SedU 



xxxyiii. 2. 



This attachment of the placenta! veffels to the irj* 

 ternal fide of the uterus by their own proper efforts 

 appears furthe.r illuflrated by the many inftances of 

 extra-uterine fetufes, which have thus attached or 

 infer ted tneir veflels into the peritoneum; or on 

 the vifcera, exadUy in the fame manner as they na-* 

 turally infert or attach them to the uterus. 



The abforbent veflels of the embryon continue to 

 drink up nourifhment from the fluid in which they 

 fvvim, or liquor amnii ; and which at firft needs no 

 previous digeftive preparation ; but which, when the 

 whole apparatus of digeftion becomes complete, is 

 fwallowed by the mouth into the ftomach, and be- 

 ing mixed with faliva, gaftric juice, bile, pancrea- 

 tic juice, and mucus of the interlines, Becomes di* 

 gefted, and leaves % recrement, which produces the 

 firft feces of the infant, called mecpnjum. 



The liquor amnii is fecreted into the uterus, as 

 the fetus requires it, and may proba^y be produced 

 by the irritation of the fetus as an extraneous body ; 

 fince a fimilar fluid h acquired from the peritoneum 

 in cafes of extra-uterine geftatipn. 'The young ca- 

 terpillars of the gadfly 'placed in the fkins of cows, 

 3nd the young of the ichneumon-fly placed in the 

 backs of the caterpillars on cabbages, feem to pro- 

 duce their nourifhment by their irritating the fides 

 of their nidus. A vegetable fecretion and concre- 

 tion is thus produced on oak-leaves by the gall- 



infedl, 



